Watch and WatchEffect in Vue Js | Vue js Series

Vue.js is a popular JavaScript framework for building user interfaces and single-page applications. It provides developers with a set of tools to create reactive and dynamic web applications. In this article, we will explore two important features of Vue.js: Watch and WatchEffect.

Watch

Watch is a powerful feature in Vue.js that allows developers to reactively execute custom logic when the value of a data property changes. This is particularly useful when you need to perform asynchronous or expensive operations in response to data changes. You can use the watch option in a Vue component to declare a watcher for a specific data property.

// Example of using Watch in Vue component
“`html

export default {
data() {
return {
inputValue: ”
};
},
watch: {
inputValue(newValue, oldValue) {
// Do something when the input value changes
}
}
}

“`

WatchEffect

WatchEffect is a new addition to Vue 3.x and is an improved alternative to the watch option. It allows developers to create side effects that reactively re-run when the data dependencies have changed. This makes it easier to write reactive code and eliminates the need to manually track dependencies.

// Example of using WatchEffect in Vue component
“`html

import { watchEffect, ref } from ‘vue’;

export default {
setup() {
const inputValue = ref(”);

watchEffect(() => {
// Do something when the value of inputValue changes
});

return {
inputValue
}
}
}

“`

Conclusion

Watch and WatchEffect are important features of Vue.js that allow developers to create reactive and efficient code. By using these features, developers can easily respond to changes in data and create side effects that update automatically. If you are working with Vue.js, make sure to familiarize yourself with Watch and WatchEffect to take advantage of their capabilities.